The present invention relates to magnetic record apparatus. More particularly, it relates to a preamplifier means for a magnetic record reproducing system.
It is the objective of any record playback system to faithfully reproduce the signals which were impressed on the recording medium, free from distortions and superimposed spurious signals known as noise. Whereas previously, in the art of magnetic recording, the distortions and superimposed noise was due largely to the coating on the tape or to the inefficiency of the reproduce head, those problems have been overcome by the advancing technology and it is now found that the limitations to the quality reproduction of the recorded signals lies in the electronic amplification system. While the referenced Braitberg patent provided a marked improvement in the electronic amplification system, the upper frequency limit in that circuit was found to be about 2 MHz. It was found, however, that when an effort was made to push the frequency response beyond 2 MHz, there was a resulting phase shift of the reproduced signal relative to the recorded signal. In such high frequency situations wherein a high accuracy is required, the phase shift is an undesirable if not intolerable characteristic.